From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from metis.ext.pengutronix.de ([2001:6f8:1178:4:290:27ff:fe1d:cc33]) by merlin.infradead.org with esmtps (Exim 4.80.1 #2 (Red Hat Linux)) id 1V1Cyo-0003q0-FC for barebox@lists.infradead.org; Mon, 22 Jul 2013 10:04:35 +0000 From: Sascha Hauer Date: Mon, 22 Jul 2013 12:04:06 +0200 Message-Id: <1374487450-13800-5-git-send-email-s.hauer@pengutronix.de> In-Reply-To: <1374487450-13800-1-git-send-email-s.hauer@pengutronix.de> References: <1374487450-13800-1-git-send-email-s.hauer@pengutronix.de> List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "barebox" Errors-To: barebox-bounces+u.kleine-koenig=pengutronix.de@lists.infradead.org Subject: [PATCH 4/8] string: introduce memchr_inv To: barebox@lists.infradead.org Directly taken from Linux Kernel. Signed-off-by: Sascha Hauer --- include/linux/string.h | 2 ++ lib/string.c | 59 ++++++++++++++++++++++++++++++++++++++++++++++++++ 2 files changed, 61 insertions(+) diff --git a/include/linux/string.h b/include/linux/string.h index 658264c..5df8c50 100644 --- a/include/linux/string.h +++ b/include/linux/string.h @@ -106,6 +106,8 @@ extern char * skip_spaces(const char *); extern char *strim(char *); +void *memchr_inv(const void *start, int c, size_t bytes); + #ifdef __cplusplus } #endif diff --git a/lib/string.c b/lib/string.c index f544b23..eeec137 100644 --- a/lib/string.c +++ b/lib/string.c @@ -666,3 +666,62 @@ char *strim(char *s) return s; } EXPORT_SYMBOL(strim); + +static void *check_bytes8(const u8 *start, u8 value, unsigned int bytes) +{ + while (bytes) { + if (*start != value) + return (void *)start; + start++; + bytes--; + } + return NULL; +} + +/** + * memchr_inv - Find an unmatching character in an area of memory. + * @start: The memory area + * @c: Find a character other than c + * @bytes: The size of the area. + * + * returns the address of the first character other than @c, or %NULL + * if the whole buffer contains just @c. + */ +void *memchr_inv(const void *start, int c, size_t bytes) +{ + u8 value = c; + u64 value64; + unsigned int words, prefix; + + if (bytes <= 16) + return check_bytes8(start, value, bytes); + + value64 = value; + value64 |= value64 << 8; + value64 |= value64 << 16; + value64 |= value64 << 32; + + prefix = (unsigned long)start % 8; + if (prefix) { + u8 *r; + + prefix = 8 - prefix; + r = check_bytes8(start, value, prefix); + if (r) + return r; + start += prefix; + bytes -= prefix; + } + + words = bytes / 8; + + while (words) { + if (*(u64 *)start != value64) + return check_bytes8(start, value, 8); + start += 8; + words--; + } + + return check_bytes8(start, value, bytes % 8); +} +EXPORT_SYMBOL(memchr_inv); -- 1.8.3.2 _______________________________________________ barebox mailing list barebox@lists.infradead.org http://lists.infradead.org/mailman/listinfo/barebox